This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Abstract: The primary goal of this project is to develop improved microcantilever-based biosensors using receptor proteins based on an acetylcholine binding protein (AChBP). The AChBP is a soluble protein that displays structure and pharmacology that is strikingly similar to the nicotinic acetylcholine receptor (nAChR) present in the central and peripheral nervous systems. Since the nAChR is a member of a large super-family of ligand gated ion channels (LGICs), this project will ultimately develop sensors that will be useful in high throughput drug screening and drug discovery for this class of neuronal receptors. Aim 1 will evaluate the AChBP itself as a potentially useful biosensor molecule. We will initially demonstrate the use of this sensor in high-throughput drug screening by exploring its interaction with nAChR, GABAR, glycineR and 5-HT3R ligands. Since the AChBP is commonly used as a template for modeling of ligand gated ion channel receptors, an additional benefit of this work will be an expanded knowledge of the basis of ligand specificity at these important receptors. Aim 2 will utilize the AChBP and other receptor proteins to improve sensor response through improved conjugation chemistries in combination with improved microcantilever array technology developed in Dr. Ji's laboratory.